An early Paleogene trogon (Aves: Trogoniformes) from the Fur Formation, Denmark

Abstract

ABSTRACT Septentrogon madseni, gen. et sp. nov. is assigned to the family Trogonidae (Aves: Trogoniformes), based on a well-preserved neurocranium from the latest Paleocene–earliest Eocene Fur Formation in north-western Denmark. The taxonomic assignment to Trogonidae is based on an overall similarity and the diagnostic character state of the zygomatic processes, being mediolaterally flattened and rounded in circumference. The specimen is identified as a separate genus and species based on slight proportional differences of the frontals, braincase and zygomatic processes. This new fossil trogon exceeds the hitherto oldest known trogon (and only other known fossil trogon with cranial elements preserved), Primotrogon wintersteini Mayr (1999) by more than 20 Ma. The significant similarity between S. madseni and extant trogons implies that trogons as a taxonomic group morphologically has stayed nearly stationary through time. The palaeoenvironment and palaeoclimate of northern Europe in late Paleocene and early Eocene corresponds well with that in which extant trogons live, and trogons may have followed the movement of the (sub-)tropical climatic belt toward the equator through the Cenozoic rather than adapt to new climatic and environmental conditions.